Many aircraft, including general aviation aircraft, unmanned air vehicles (UAVs), missiles, and experimental and research aircraft, use various pressure and other sensors and associated signal processing circuits to determine various flight-related “air data” and other parameters. For example, many aircraft include a plurality of pressure sensors to sense at least static pressure and total pressure during aircraft flight. The subsequent signal processing circuits, using pressure signals derived from the pressure sensors, calculate air data parameters representative of various flight-related conditions. Such data may include, for example, Mach (M), calibrated airspeed (CAS), aircraft altitude, angle of attack (AOA), and angle of slip (AOS), just to name a few. Recently, sensors and selected processing circuits have been packaged together into what may be referred to as an integrated sensor system (ISS). In contrast to prior discrete component implementations, an ISS has the sensor and associated signal processing circuitry co-located within the sensor package.
An ISS typically includes a sensor die, which may include just a pressure sensor or both a pressure sensor and a temperature sensor. The temperature sensor, if included, is typically provided to aid in temperature compensation of the pressure measurement. The ISS also typically includes signal conditioning, data conversion, control, and memory circuits for use in conjunction with an external microcomputer. The signal conditioning and data conversion circuits, which are in many instances implemented as amplifier-based circuits, supply appropriate sensor signals representative of the sensed pressure and or temperature for use by external circuitry.
It may be appreciated that the configuration of the output signals provided by an ISS may vary depending, for example, on the type of signal processing that is implemented by the external end-use circuits. For example, if the end-use circuit is an analog system, then the ISS will need to provide an analog signal. Similarly, if the end-use system is a digital circuit, then the ISS will need its output to be configured as a digital signal. Although presently known ISSs are generally safe, reliable, and robust, these systems can exhibit certain drawbacks.
For example, many ISSs do not provide adequate interface flexibility and measurement capability, and/or adequate measurement resolution for air data and other low-noise precision applications. Many ISSs also exhibit relatively excessive latency for wide bandwidth control systems, and/or insufficient measurement accuracy and stability over time, temperature, and humidity, and/or insufficient reliability due to non-hermetic packaging, and/or limited interface configurability to meet system needs. Moreover, many so-called “smart sensors” (those with an internal microcomputer) have inadequate capability to perform high accuracy pressure measurements (>20 bit resolution) at the high measurement rates (>200 Hz) that may be needed for air data and other applications requiring low latency (<5 ms).
Hence, there is a need for a precision, environmentally-compatible, integrated sensor system that incorporates a sensor, signal conditioning circuitry, and appropriate interface circuitry within a single housing, and is compatible with a multiplicity of both analog and digital end-use circuits. Furthermore, other desirable features and characteristics of the present invention will become apparent from the subsequent detailed description of the invention and the appended claims, taken in conjunction with the accompanying drawings and this background of the invention.